EP0952084A1 - Process and apparatus for heat shrinking a synthetic film tube around a gas bottle and the obtained bottle - Google Patents

Abstract

To heat-shrink a shrouding of synthetic material round a gas bottle (40), the shrouding is wrapped round a vertical bottle to be placed in a ring heater (14). The heater has an upper preheating zone with a heating level (E1) and a lower heat shrinking zone with a second heating level (E2) which is higher than the first level (E1). The ring heater (14) movement is in two phases. In the initial phase, the heater (14) is lowered round the gas bottle (40) at a high speed to give the heat shrinking round the bottle base, and then the heater is raised in a second phase and at a slower speed. An Independent claim is included for an apparatus with a frame to support the movements of a ring heater (14). The inner diameter (D) of the heater (14) is larger than the maximum gas bottle (4) size to be used. The inner heater (32) at the bottom one-quarter of the heater height generates a higher heat level (E2) than the heater (30) covering the remainder of the ring heater height. The ring heater (14) is moved up and down by an arm which slides on the support frame. The frame assembly has motors to move the support arm up and down at different speeds. A control unit sets the heating power supplies to the heaters (30,32) and the motor supply currents. Preferred Features: The ring heater (14) has an inner ferrule (25), fitted with two sets of electrical resistance spiral coil heaters (30,32) each with its own power supply circuit. The gaps (P2) between the coils in the lower heater (32) are smaller than the gaps (P1) between the coils in the upper heater (30). The heating coils with the inner ferrule are within a shrouding (29) of thermal insulation. The insulated shrouding (29) has at least one ventilation opening, leading to the outside, opposite a ventilating air flow. The heater support arm has two cylindrical tenons, at the end away from the heater, as a linkage to be rotated partially by motors to align the center of the ring heater (14) over the center axis of the gas bottle (40) at one of the working positions. Each working position has a solid metal support (22) as a heat accumulator. A further Independent claim is included for a gas bottle, where the heat-shrinking synthetic bottle shrouding material is opaque, and is applied only to the cylindrical section (40a) of the gas bottle (40). Preferred Features: The heat-shrinking synthetic shrouding material can be translucent, covering the cylindrical section (40a) and also the domed head (40b) of the bottle (40). The shrouding retains an electronic memory between it and the bottle head section, which contains the bottle identification data which can be scanned remotely.

Description

The invention relates to a method and a device for heat shrink a plastic sheath on a gas cylinder, that is to say on a cylindrical container intended to withstand pressure high internal.

Currently, pressurized gas cylinders, for use industrial or medical, come in different dimensions ranging from diameters, from 140 to 245 mm, and for their height, from value from 420 to 1,500 mm. Each bottle is made up of an envelope thick metal with, at its base, a curved bottom welded on a stabilization base and, at its top, an ogival head fitted with a valve closure with connecting end piece.

Traditionally, indications for pressure testing of the bottle, the nature of the gas contained in that bottle, and the gas supplier, are stamped on the outside of the ogival head which, very often, is covered with a layer of paint whose color depends on the nature of the gas.

Currently, the protection of the external surface of the bottle is provided by a layer of paint which must be renewed at least once between two bottle proof tests and after each proof test. This renovation is carried out by means of a long and tiring operation since, requiring manual movement of containers having a mass unladen from 15 to 35 kg. In practice, the renovation rate is the order of 40 bottles per man per day, not including the time of paint drying.

To improve the protection of the external face of the bottle against oxidation, but also against shocks, while seeking to increase the rate of implementation of this protection, it was envisaged to surround the container by a shrinkable plastic sheath, in addition large transverse dimension than the diameter of the bottle in front of the receive, and ensure this shrinkage by heating.

It then appeared that the technique of moving the containers by placing them vertically on a conveyor to pass them in a heating tunnel, was not satisfactory due, on the one hand, to the lack of stability of the container having a reduced lift surface by relative to its height and, to its mass, and secondly, due to the heterogeneity of the shrinkage of the sheath on the bottle.

Indeed, it appeared, for all types of bottle, that the sheath shrinkage which depends on local temperature gradients which can be different on its height, is done randomly by favoring entrapment of air pockets forming protrusions that spoil the appearance final aesthetics of the bottle.

Another technique, consisting of arranging horizontally each bottle by placing it by its ends on movable supports longitudinally, is not satisfactory either, for two reasons. The first is that this technique requires physical effort important to lift and lay down each bottle, then later the lift and straighten it. The second is that not only does it improve not the elimination of air pockets, but on the contrary favors it, since, during from the passage in a heating tunnel, the heat-shrinkable sheath heated tends to hang in a loop under the bottle, thus forming, under this bottle, a part whose retraction takes place even more irregularly and promotes the imprisonment of air pockets.

The object of the present invention is to remedy these drawbacks by providing a method for obtaining a homogeneous retraction of a heat shrink tubing on a gas cylinder arranged vertically to obtain a smooth and regular coating, with no visible air pocket, while requiring minimal physical effort.

This process consists in engaging the sheath around the bottle of gas arranged vertically, to be moved vertically around the bottle an annular heat source comprising an upper zone of sheath preheating, providing heat energy per unit of surface of value E1, and a lower zone of shrinkage of the sheath providing heat energy per unit of area of value E2, greater than E1.

Thus, the heat-shrinkable sheath is first subjected to a preheating which raises its temperature without causing too much retraction, then to a more violent heating which causes its sudden retraction. The combination of this brutal retraction with the displacement of the source annular with respect to the bottle form, in front of the retracted area of the sheath, a cone which, as it moves, expels before it the air contained between the sheath and the peripheral face of the container, substantially in the same way as human hands would smooth the sheath as you go of its retraction. As a result, the air contained between the sheath and the bottle is removed as and when the coating thus obtained is free from any air pocket.

The value of the calorific energies released by the source annular, as well as the speed of movement of this source, are determined according to the chemical-physical characteristics of the material synthetic material used and the diametrical dimension of the gas cylinder.

In one form of implementation, the displacement of the source annular heat is carried out in two phases, namely a first phase during which the heat source is lowered, at high speed V1, around the bottle to bring its downstream retraction area around the bottom domed with this and a second phase of rise at speed V2, of value less than V1.

Under these conditions, the first rapid descent phase ensures sheath preheating, without triggering any shrinkage but allows the downstream area of retraction to come to the level of the convex bottom of the bottle for, during the reversal phase, and thanks to the high energy heat of this zone, ensure the drawdown by retraction of the end lower of the sheath on the convex bottom of the bottle. This drawdown subsequently contributes to the setting in longitudinal translation of the coating on the bottle.

The invention also relates to the device for the implementation of this process.

• un bâti,
• un manchon chauffant d'axe longitudinal vertical et de diamètre intérieur supérieur à celui extérieur de la plus grande bouteille de gaz pouvant être rencontrée, ce manchon portant sur, sensiblement le quart inférieur de sa hauteur, des moyens de production de chaleur dégageant une énergie calorifique par unité de surface supérieure à la valeur de l'énergie calorifique par unité de surface dégagée par les moyens de production de chaleur disposés sur le reste de sa hauteur,
• un bras reliant le manchon à un coulisseau mobile sur des glissières verticales du bâti,
• des moyens moteurs aptes à déplacer le coulisseau dans les deux sens et avec des vitesses différentes et réglables,
• et des moyens de commande régissant l'alimentation des moyens de chauffage et des moyens moteurs de déplacement vertical du manchon.

This device includes:

• a frame,
• a heating sleeve with a vertical longitudinal axis and an inside diameter greater than that outside of the largest gas cylinder that can be encountered, this sleeve bearing on, substantially the lower quarter of its height, means for producing heat releasing heat energy per unit of surface greater than the value of the calorific energy per unit of surface released by the means of heat production arranged on the rest of its height,
• an arm connecting the sleeve to a movable slide on vertical rails of the frame,
• motor means capable of moving the slide in both directions and with different and adjustable speeds,
• and control means governing the supply of the heating means and motor means for vertical displacement of the sleeve.

In one embodiment, the sleeve includes a ferrule interior on the interior face of which are fixed, at least two spiral electrical resistance assemblies, each supplied by a circuit distinct, the set of resistors arranged on the lower part of the shell having a winding pitch less than that of the winding pitch of the set of resistors arranged in the upper part, said ferrule being surrounded by a ferrule of larger diameter than it, with which it forms an annular box containing a thermal insulator.

Due to its structure, the heating sleeve can indifferently be used for heat shrinking on containers having a diameter ranging from the smallest to the largest dimension, i.e. having a diameter ranging from 140 to 245 mm, since the power The heat emitted by the resistors can be regulated as required.

Depending on the applications, the plastic sheath is opaque or translucent and extends from the base of the container covering only its cylindrical part or its cylindrical part and its ogival part.

In a preferred application, the coating extends to the head ogival and traps against this ogival head, an electronic memory containing identification data, readable remotely, by a unit of reading.

This provision eliminates any transaction stamping on the ogival part to indicate the last date the supplier, and the gas contained in the container, since these data are included in the electronic memory which can also contain for each refill, the date and the volume transferred, or any other data promoting the management or distribution of bottles. By its position on the ogival head, the electronic component is perfectly protected against shocks, while remaining accessible for reading means, even when the bottle is juxtaposed with another bottle.

Figure 1 est une vue en perspective éclatée de la partie inférieure du dispositif,

Figure 2 est une vue de côté en coupe transversale partielle, lorsqu'il est en début de positionnement sur une bouteille,

Figure 3 est une vue de côté en élévation d'une bouteille avec coupe partielle du manchon chauffant au début de la phase de montée rapide,

Figure 4 est une vue en plan par dessus de l'installation,

Figure 5 est une vue partielle de côté en élévation avec coupe partielle de la partie supérieure d'une bouteille de gaz équipée d'une mémoire électronique.

Other characteristics and advantages will emerge from the description which follows with reference to the appended schematic drawing representing, by way of example, an embodiment of the device for implementing the method and of the bottles thus coated.

FIG. 1 is an exploded perspective view of the lower part of the device,

FIG. 2 is a side view in partial cross section, when it is at the start of positioning on a bottle,

FIG. 3 is a side elevation view of a bottle with partial section of the heating sleeve at the start of the rapid rise phase,

FIG. 4 is a plan view from above of the installation,

Figure 5 is a partial side view in elevation with partial section of the upper part of a gas cylinder equipped with an electronic memory.

In this drawing, the reference numeral 2 designates a frame composed of a sole 3 carrying two pairs of vertical slides 4 for a movable slide 5. The slide 5 carries two pairs of rollers 6, of axis horizontal, and, in each pair, the superimposed rollers circulate between the vertical slides of a pair of slides 4. The slide is connected to motor means which, in this embodiment, consist of a electric motor 11, the output shaft of which carries a drive pulley 7 on which runs a cable 8 connecting the slider 5 to a counterweight 9. A return pulley 10 is mounted to rotate freely on a horizontal axis 12 carried by the frame. The slide carries an arm 13 at the end of which is fixed a annular heating sleeve 14.

The device shown comprises two work stations A1 and A2, as shown in FIG. 4. The arm 13 is provided, at its end opposite to that carrying the sleeve 14, that is to say at its end on the frame side, of two vertical coaxial tenons, respectively upper 15a and lower 15b. These pins are mounted free to rotate in a yoke 16, carried by the slide 5, and the pin 15a is linked in rotation to a toothed wheel 17, itself connected by a chain 18 to a drive gear 19. The latter is wedged on the vertical shaft of an electric motor 20 carried by the slide 5 in the interval between the two pairs of vertical slides 4.

These drive means 17, 18, 19, 20 therefore make it possible to make pivot the arm 13 and the sleeve 14 constituting the annular heat source, on a fraction of a turn, that is to say of the order of 15 to 30 °, on both sides of the median plane P of the device (FIG. 4).

Each work station A1, A2 is provided with a sole 22 made up by a very thick circular and metallic disc having the function of facilitate the positioning of a bottle, but also to accumulate heat transmitted to the bottle by retraction.

The arm 13 is provided with means positioning it, in each station, so that the vertical axis of the sleeve 14 is substantially coaxial to the vertical axis of the sole. In the embodiment shown, these means consist of the two wings of a V-bracket, welded to the yoke 16 of the slide 5, as shown in FIGS. 1 and 4.

As shown in more detail in Figure 3, the heating mantle 14 is composed of an internal ferrule 25 which is connected to an external ferrule 26 by an upper crown 27 and by a lower crown 28. The cavity annular 29, thus formed, is filled with an insulating material reducing heat losses to the outside, such as rock wool.

On the inner face of the inner shroud 5, two are fixed sets of electrical resistances, namely an upper set 30 and a lower assembly 32. The upper assembly 30 extends over a height L1 corresponding substantially to three quarters of the height of the sleeve, while that the lower assembly 32 extends over a corresponding height L2 substantially at the lower quarter of the height of the sleeve. The resistances are in spirals and are fixed against the shell 25 by jumpers 33. The pitch P2 of distribution of the turns of the lower resistance set 32 is lower than the pitch P1 of distribution of the turns of the upper assembly, so as to be able to release a heat energy per unit of area E2 higher than that E1 released by the upper set 30 of resistors upper 30, under the same power supply conditions. These two sets 30 and 32 are supplied by separate circuits, through a control and regulation unit 35 (FIG. 4) also comprising the means for controlling the supply of electric motors 6 and 20. carried by the frame.

The amount of current supplied to each of sets 30 and 32 and therefore its calorific value is determined on a piecemeal basis depending on the diameter of the bottle, and therefore the importance of space radial between the sheath 42 and the resistance, but specific characteristics of this sheath 42.

It is obvious that the internal diameter D of the sets of resistance has a value greater than the larger diameter of the bottles that can be accepted, and for example, is of the order of 570 mm for a sleeve that can accommodate bottles with diameters ranging from 140 to 245 millimeters.

Figure 1 shows that the annular cavity 29 of the sleeve communicates with the outside through a ventilation opening 36. To avoid the accumulation of calories in this annular cavity, this can be connected, opposite the opening 36, to an air flow generator of ventilation, not shown.

To heat shrink a plastic sheath 42 on a gas cylinder 40, by means of this device, the cylinder 40 is first brought to one of the A1 or A2 stations, for example by rolling its bottom, until its base 41 rests on the sole 22, with its vertical axis x'-x passing, substantially, through that of said sole, as shown in FIG. 2. note that this installation operation can be carried out with the bottle already fitted with a heat-shrinkable sheath 42, because it is placed outside the heat shrink installation.

This sheath 42 can extend only over the cylindrical part 40a of the bottle, as shown in FIG. 3, or on this cylindrical part 40a and the ogival part 40b, as shown in FIG. 2. In the first case, the sheath is opaque, and does not extend over the ogival part so as not to obscure the indications marked by punching thereon, while in the other case, it is translucent and allows, after its retraction, to read the indications worn by punching on the ogival part 40b of the container.

When the container 40 and the sheath 42 are positioned on the floor 22, the arm 13, then in the high position, is pivoted so as to bring the axis longitudinal of the sleeve 14 coincident with that of the bottle 40. This pivoting is ensured by the motor 20 which, by the transmission 19, 18 and 17, causes the arm to pivot about the axis of its tenons 15a, 15b until abut the corresponding wing of the bracket 23. At this point, the engine electric 11, causing the vertical movement of the slide 5 on the slides 4, is powered to bring down the arm 13 and the sleeve 14 at a fast speed V1. This movement takes place until the base of the sleeve 14 comes substantially at ground level, and while the sets of resistors 30, 32 are supplied and provide. due to rapid speed, preheating of the sheath 42, without causing the retraction. When the sleeve 14 reaches the lower end of travel, the motor 11 is supplied in the opposite direction, so as to ensure vertical displacement towards the top of this sleeve, but with a speed V2 lower than V1. The reversal of direction, and possibly a timed stop, allowing the lower resistance assembly 32, giving off violent energy calorific to fold down the lower end of the sheath 42, under the domed bottom 40c of the bottle. This thus forms a flap 46 which protects this part and above all contributes to the setting in longitudinal translation of the sheath on the bottle.

This retraction on the curved bottom 40c takes place all the more easily that it benefits from an additional calorific contribution. Indeed, the sole 22, which has accumulated the heat transmitted by a gas cylinder having undergoes a retraction, does not transmit this heat, by direct conduction, to the bottom of the bottle put in place in anticipation of the next operation, and of this bottle to the sheath, thereby ensuring that it is preheated.

During the longitudinal upward movement of the sleeve 14, the set of resistors 30 ensures the preheating of the sheath, while the lower assembly 32 causes its violent retraction on the container. In the transition zone between the retracted part and the non-retracted part of the sheath, there is thus formed a kind of cone 47 which, in combination with the displacement of the sleeve 14, expels in front of it the air trapped between the sheath 42 and the outer face of the bottle, as the human hand would smooth the sheath on the bottle. As a result, as the displacement of the sleeve, the air is expelled upwards, which removes any formation of air pocket between the sheath and the bottle and contributes to obtaining a coating perfectly smooth finish. As soon as the sleeve reaches above the coating, its upward movement can be accelerated to facilitate the bottle release. At the end of the vertical stroke, the sleeve is moved angularly by the arm 13 to come above the work station A2, where another gas cylinder with its sheath 42 was put in place, during the heat-shrinking operation at station A1.

It appears from the above that the device according to the invention considerably reduces the time required for installation of a coating on a gas cylinder, to simplify the handling of setting up and extracting bottles and thus increasing considerably the rate of work.

For example, with a double station device comprising a heating ring working 1.5 minutes per shift, a man can put on 360 bottles per day, which is much higher than a rate of 40 bottles / day with a painted coating. In addition, depending on applications, it is very easy to replace a colored sheath with a sheath of different coloring.

Thanks to this device, the bottles are protected by a protective coating which not only improves their aesthetic appearance, but also protects them effectively for shocks. This amortization of impact depends on the thickness of the coating and is adapted according to the needs.

In one form of implementation, shown in FIG. 5, the coating 50 thus produced extends over the cylindrical body 40a and over the head ogival 40b of the bottle and traps against this head a memory electronic 52, such as a chip, a transponder or the like. This memory can thus contain identification data of the bottle, and for example his number, his last test date, but also his containing, from its last filling date, its conditions of filling and, in general, any other information favoring the management or distribution of the bottle and can be read remotely by a reading unit. This unit can also be a writing unit modifying the data included in the memory.

Claims (10)

Method for heat shrinking on a gas cylinder (40) a sheath (42) of heat shrinkable plastic, characterized in that it consists in engaging the sheath (42) around the gas cylinder (40) arranged vertically, to be moved vertically around the bottle and the sheath, an annular heat source (14) comprising an upper zone for preheating the sheath, providing heat energy per unit area of value (E1), and a lower zone for shrinking the sheath, providing heat energy per unit area of value (E2), greater than (E1). Method according to claim 1, characterized in that the displacement of the annular heat source (14) is carried out in two phases, namely a first phase during which the heat source is lowered, at high speed (V1), around the bottle (40) for bringing its lower retraction zone around the curved bottom thereof and of a second phase of rise, at speed (V2), of value less than (V1). Device for implementing the method according to either of Claims 1 and 2, characterized in that it comprises: a frame (2), a heating sleeve (14) with a vertical longitudinal axis and an inside diameter (D) greater than that outside of the largest gas cylinder (40) that can be encountered, this sleeve bearing on, substantially the lower quarter of its height, means (32) for producing heat releasing a heat energy (E2) per unit area greater than the value (E1) of heat energy per unit area released by the means (30) for producing heat arranged on the rest from its height, an arm (13) connecting the sleeve (14) to a slide (5) movable on vertical slides (4) of the frame (2), motor means (6, 7, 8) able to move the slide (5) in both directions and with different and adjustable speeds, and control means (35) governing the supply of the heating means (30, 32) and motor means (6) for vertical movement of the sleeve (14). Device according to claim 3, characterized in that the sleeve (14) comprises an inner ferrule (25) on the inner face of which are fixed, at least two sets (30, 32) of electrical resistance in a spiral, each supplied by a separate circuit, the set (32) of resistors arranged on the lower part of the shell having a winding pitch (P2) of value less than that of the pitch (P1) of winding the set (30) of resistors arranged in the upper part, said ferrule (25) being surrounded by a ferrule (26) of larger diameter than it, with which it forms an annular box (29) containing a thermal insulator. Device according to claim 4, characterized in that the annular box (29) communicates with the outside by at least one ventilation opening (36) and is connected, opposite this opening (36), to a flow ventilation air. Device according to claim 3, characterized in that the arm (13) carrying the sleeve (14) is provided, at its end opposite to that linked to this sleeve (14), with two vertical cylindrical tenons (15a, 15b) by which it is articulated in a yoke (16) of the slide (5) and one (15a) of the studs is linked in rotation to motor means (17, 18, 19, 20) able to rotate it by a fraction of turn on either side of the vertical median plane of the frame to bring the longitudinal axis of the sleeve (14) into coincidence with the vertical axis of one of the positioning stations (A1, A2) of a gas cylinder (40) distributed around the frame (2). Device according to claim 3, characterized in that each positioning station (A1, A2) of a gas cylinder (40) is delimited by a metal and massive sole (22), constituting a thermal accumulator. Gas cylinder coated by the method according to claim 1 and comprising a cylindrical body and an ogival head (40b), characterized in that the sheath (42) coating it is made of an opaque heat-shrinkable synthetic material extending only over its cylindrical part (40a) and stopping at the limit between this part and its ogival head (40b). Gas bottle coated by the method according to claim 1 and comprising a cylindrical body (40a) and an ogival head (40b), characterized in that the sheath (42) coating it is made of a translucent heat-shrinkable synthetic material and extends on the cylindrical body (40a) and on the ogival head (40b). Gas bottle coated by the method according to claim 1 and comprising a cylindrical body (40a) and an ogival head (40b), characterized in that the coating extends over the body and over the head of the bottle and traps against the ogival head an electronic memory (52) containing identification data readable remotely by a reading unit.

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